or SEXAGESIMAL Fractions, fractions whose denominators proceed in a sexaguple ratio; that is, a prime, or the first minute = \(\frac{1}{60}\); a second = \(\frac{1}{3600}\); a third = \(\frac{1}{216000}\). Anciently, there were no other sexagesimals used in astronomy; and they are still retained in many cases, though decimal arithmetic begins to grow in the now in astronomical calculations. In these fractions, which some call astronomical fractions, the denominator being always 60, or a multiple thereof, is usually omitted, and the numerator only written down: thus \(4^o\), \(59'\), \(32''\), \(50'''\), \(16''''\) is to be read, 4 degrees, 59 minutes, 32 seconds, 50 thirds, 16 fourths, &c.